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United States Patent |
6,006,673
|
Brandt
|
December 28, 1999
|
Cylinder type rail car indexer
Abstract
A rail car indexer that provides a continuous transfer of the rail car
bogeys from one dog to the next without ramming into the rail car axles in
either the forward or rearward directions. The rail car indexer includes
two parallel linearly offset progressor each of which has a barney and dog
attached thereto. A center balance and back pressure bypass valve are used
to control the raising of the dogs and to insure that the dogs remain in
their lowered position until the proper progressor is ready to begin
pulling on the rail car bogey axle. Sensors and a photo eye emitter and
receiver coordinate the extension, retraction and transfer of an axle
between the progressors.
Inventors:
|
Brandt; Calvin J. (Delano, MN)
|
Assignee:
|
Motion Controls, Inc. (Delano, MN)
|
Appl. No.:
|
069506 |
Filed:
|
April 29, 1998 |
Current U.S. Class: |
104/162 |
Intern'l Class: |
B61B 013/00 |
Field of Search: |
104/165,162
198/736,738,746
|
References Cited
U.S. Patent Documents
3146728 | Sep., 1964 | Doorley | 104/162.
|
3377961 | Apr., 1968 | Hunt | 104/162.
|
3696754 | Oct., 1972 | Anderson et al.
| |
4006691 | Feb., 1977 | Kacir et al.
| |
4252064 | Feb., 1981 | Ratchliff, Jr. et al.
| |
4354792 | Oct., 1982 | Cornish.
| |
4926755 | May., 1990 | Seiford, Sr.
| |
5287812 | Feb., 1994 | Lobb et al. | 104/162.
|
5709153 | Jan., 1998 | Brandt.
| |
Primary Examiner: Le; Mark T.
Attorney, Agent or Firm: Nikolai, Mersereau & Dietz, P.A.
Claims
What is claimed is:
1. An apparatus for shifting a line of railroad cars comprising:
(a) first and second staggered parallel fluid operated linear primary
actuators, said primary actuators comprising a plurality of serially
connected simultaneously operated double acting fluid cylinders which
extend and retract together and each said primary actuator further
comprising a stationary and one or more tandem cylinders including an end
tandem cylinder bearing a free end and a fluid supply and return line
connected to each of said primary actuators;
(b) first and second pivotally mounted axle addressing dogs carried by said
first and second primary linear actuators and connected to the free ends
of the end tandem cylinders;
(c) first and second fluid operated linear dog pivoting actuators for
respectively moving said first and second axle addressing dogs between a
lowered stowed position and a raised axle addressing position;
(d) a fluid operating system connected to operate said linear primary
actuators and said dog pivoting actuators;
(e) first and second sensing means carried respectively by a moving
cylinder of said first and second primary linear actuators for sensing the
presence of consecutive wheels of a railroad car bogey carriage;
(f) control means responsive to said first and second sensing means for
controlling the operation of first and second primary linear actuators and
said first and second dog pivoting actuators; and
(g) wherein said control means further includes means for preventing the
raising of a dog during extension of a primary actuator and means for
maintaining a dog in the raised position during retraction.
2. The apparatus of claim 1 wherein said means for preventing the raising
of the dog during extension of a primary actuator further comprises a
relief valve in the fluid supply and a biasing spring in said dog pivoting
actuator resisting raising of the dog, said relief valve being set below a
force needed to raise said dog.
3. The apparatus of claim 1 wherein said means for retaining said dog in
the raised position during retraction includes a counter-balance drain
valve having a pilot operating port in said fluid return line which
maintains system back pressure above that required to raise said dogs.
4. The apparatus of claim 3 wherein said counter-balance drain valve is
pilot operated and wherein said pilot port is connected to lines connected
to sense pressure of both supply and return fluid.
5. The apparatus of claim 4 wherein a respective fluid line is connected to
said pilot port via a shuttle OR valve.
6. The apparatus of claim 1 wherein said first and second primary actuators
extend when in a return mode.
7. The apparatus of claim 4 wherein said first and second primary actuators
extend when in a return mode.
8. The apparatus of claim 1 wherein said stationary and tandem cylinders
comprise hollow rods including multiple concentric rod lumens comprising
an inner and an outer rod lumen, said inner rod lumen being defined by a
tubular member carried centrally in said outer lumen.
9. The apparatus of claim 8 wherein said inner lumens of rods of
consecutive cylinders are connected together and between a blind end of
the stationary cylinder and the dog pivoting actuator and wherein said
outer rod lumens are connected to rod ends of said cylinders which are, in
turn, connected together.
10. The apparatus of claim 1 wherein each primary actuator includes one
tandem cylinder.
11. The apparatus of claim 1 further comprising regeneration means for
adding return fluid to supply fluid when either of said primary actuators
is extended.
12. The apparatus of claim 11 wherein said regeneration means further
comprises a check valve in said return line between said return line and
said supply line.
Description
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates generally to railway car handling equipment
and, more particularly, to a rail car spotting or indexing system which
positions railroad cars along a specified section of track to be addressed
during loading or unloading operations. Specifically, the invention deals
with an improved cylinder-type, axle progressing system having dual
coordinated progressors of variable-stroke and speed, wherein the position
of each dog of each progressor is automatically controlled.
II. Discussion of the Related Art
Freight hauling railway cars are positioned near freight or cargo handling
equipment during loading and unloading operations. Freight in the form of
bulk cargo such as grain, coal, iron or the like is typically lifted or
dumped into railway cars. Subsequently, the freight is emptied from the
cars by gravity and received by stationary freight handling equipment such
as chutes and conveyor equipment. Liquid bulk cargo is typically unloaded
by opening drain valves connected to large hoses and associated pumping
equipment. A railway car used for transporting coal, grain, or other
finely divided dry bulk agriculture material is typically covered and has
a plurality of spaced bottom discharge hopper bins or chutes accessing the
main storage volume and closed by discharge gates. This type of rail car
is designed to be positioned over dedicated recessed receiving facilities
situated at fixed stations, such as grain or coal bins and conveyors
positioned beneath the railroad track.
During the unloading operation of a coupled string of rail cars, a
connected train engine roughly positions one end of the string of cars
near the unloading area. Train engines are not well suited for indexing or
precisely positioning individual cars or even sets of cars along the
railroad track, let alone over individual car bins, chutes or conveyors.
To this end, positioning devices known as railway car indexers or spotters
have been built and operated at fixed stations.
Railway car indexers include at least one engaging member or "dog" for
engaging at least one railway car in a string of cars and pushing or
pulling the string a given distance along the railroad track. The engaging
member is often situated and operated along an auxiliary indexer track or
guideway juxtaposed in parallel relation to the railroad track in the
fixed receiving facility. Fluid-operated actuators, such as chains and
sprockets driven by hydraulic or electrical motors supply power are
provided for moving the railway cars. The dogs of these devices typically
operate against the lower or upper portion of the railroad car wheel truck
frame (bogey frame). One such device is illustrated and described in
co-pending application Ser. No. 08/580,810, filed Dec. 29, 1995, now U.S.
Pat. No. 5,709,153, issued Jan. 20, 1998, and entitled "HIGH DOG INDEXER".
That application is common of inventorship and assignee with the present
application.
U.S. Pat. No. 4,006,691 issued to Kacir et al. and U.S. Pat. No. 4,354,792
issued to Cornish show train positioners including an engaging member arm
which engages a car coupler from above. The engaging member arm is
situated on a track or guideway next to the railroad track. Power is
supplied to the positioner for moving the railway cars by a motor
connected to a pulley and cable assembly. These positioners are quite
large and complex, and initially aligning the railway cars with the
engaging member arm such that the arm may be lowered to engage the car
coupler may be difficult.
U.S. Pat. No. 3,696,754, issued to Anderson et al, describes a railroad car
shifting system mounted between the tracks which employs axle engaging
dogs pivotally attached to dog carriages or barneys which are situated in
a guideway. Each dog is spring-biased to a raised position for engaging
and pushing the next railroad wheel axle encountered as the barney is
moved in one direction along the guideway by a hydraulic cylinder. Each
dog in the '754 patent pivots to a lowered position when pushed or hit
from behind (as on a return stroke), but must be manually depressed to
allow a reversal of the direction of the string or trip of cars. The
system includes a variable-stroke hand-off system having a pair of
telescoping, single acting hydraulic actuators situated in a partially
overlapping parallel arrangement. In the stowed position the piston of at
least one of the actuators is exposed. The actuators are linked by a
common cable and sheave arrangement in which the extension of one actuator
in a power stroke pulls on the cable which, in turn, causes the collapse
or retraction of the other. In operation, the dogs alternately engage the
axles of the successive carriages in cars using a variable stroke
operation. A long vane and lever arm are used to control the stroke of
each actuator. Apparently, each actuator extends past a respective bogey
axle and then the actuator reverses direction, forcing the dog into the
axle. The distance that the actuator extends past the forward edge of the
vane must be greater than the distance between the axles of each bogey. It
is not apparent from the Anderson disclosure that the wheel axle smoothly
transfers from one dog to the other.
A later patent (U.S. Pat. No. 4,252,064 to Ratcliffe, Jr.) discloses dogs
that pivot to a lowered position when pushed or hit from behind (as on a
return stroke), and may be lowered with an auxiliary hydraulic
cylinder-operated mechanism when reversing the direction of travel of the
cars.
U.S. Pat. No. 4,926,755, issued to Seiford, Sr., describes a reversing
railway car moving system including a double truck assembly which operates
in a guide track alongside the railroad track. Each truck of the double
truck assembly includes two engaging members which are hinged together and
spring biased to a raised position to form a peak at the hinge. In the
raised position, the two trucks form a valley in which the bogey wheel
truck frame is engaged on the lower portion for movement in either
direction. A hydraulic cylinder in each truck is extended to lower the
engaging members such that a railway car may freely pass over the double
truck assembly. This reversing railway car moving system is powered by a
cable and winch, and a double truck assembly may be positioned on one or
both sides of the railroad track. Railway car indexers including a low dog
which engages the lower portion of the truck frame work fine if the
railway car is loaded to provide downward acting forces on the truck frame
to prevent derailing. However, low dog engaging members may tend to lift
the truck frame from the railroad track if the railway car is empty.
While these earlier arrangements have provided generally satisfactory
operation, there remains the need to simplify the system by reducing the
necessary moving parts and exposed mechanisms to improve operation and
reduce the need for maintenance. The elimination of sheaves and cables or
chains from the operation of such a system would clearly present an
advantage. In addition, a simplification of the mechanical complexity
associated with the operation of the dogs, together with better automation
of the raising and lowering of the dogs is definitely desirable as is a
reduction of the parts exposed to the environment when the system is not
in use.
SUMMARY OF THE INVENTION
The purpose of the present invention is to provide a rail car indexer that
automatically moves a series of coupled rail cars with a continuous hand
off or alternate transfer of the rail car bogeys between coordinated dogs.
The operation including transfer from one dog to the next is accomplished
without the drawback associated with dogs ramming into the rail car axles
during motion by either the forward or rearward directions. The rail car
indexer includes a pair of closely spaced, parallel, linearly offset
progressors motivated between the rails each of which has a barney and dog
attached thereto. The progressors are operated by fluid hydraulics and the
operation is controlled by a programmable logic controller. Counter
balance and back pressure bypass valves are connected in-line in the fluid
hydraulic system to insure that the dogs remain in their lowered position
until the proper progressor is ready to begin pulling on the rail car
bogey axle. Sensors and a photo eye emitter and receiver coordinate the
extension, retraction and transfer of an axle between the progressors.
OBJECTS
It is accordingly a principal object of the present invention to provide a
fluid operated axle progression system for railroad cars which eliminates
the need for interconnecting cables, sheaves, chains and other high
maintenance devices.
Another object of the present invention is to provide an automatic, fluid
operated, axle progression system wherein both the speed and stroke of
progression is varied automatically.
A further object of the present invention is to provide an automatic, fluid
operated, axle progression system wherein the speed of each progressor
automatically varies independent of the speed of the other progressor.
Another object of the present invention is to provide a continuous transfer
of truck axles between the forward and rearward progressors wherein the
lengths of short and long transfers may vary over the entire chain of rail
cars.
Still another object of the present invention is to improve automation with
respect to coordinating the raising and lowering of the dogs in a manner
which reduces the complexity of the dog-operating mechanism.
Yet another object of the present invention is to provide a fluid operated
axle progression system which uses regeneration.
A still further object of the present invention is to provide a counter
balance valve and back pressure by-pass valve in an automated system to
control operation of the dogs.
These and other objects, as well as these and other features and advantages
of the present invention will become readily apparent to those skilled in
the art from a review of the following detailed description of the
preferred embodiment in conjunction with the accompanying claims and
drawings in which like numerals in the several views refer to
corresponding parts.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary side elevational view partially in section of
several rail cars connected as part of a trip of cars being progressed by
a rail car indexer of the present invention;
FIG. 2 is a fragmentary top plan view showing the forward progressor fully
extended with dog raised and engaging an axle of the rail car and the
rearward progressor shown fully retracted;
FIG. 3 is a fragmentary top plan view similar to FIG. 2 just after a hand
off from the forward progressor to the rearward progressor showing the
rearward progressor fully extended with its dog raised and engaging an
axle of the rail car and the forward progressor fully retracted;
FIG. 4 is a simplified schematic side elevational view partially in section
to illustrate one possible embodiment of the progressor of the rail car
indexer of the present invention;
FIG. 5 is an enlarged schematic view with parts broken away of trunnion and
sliding cylinders showing the external mechanical and hydraulic
connections;
FIG. 6 is an enlarged view of a trunnion cylinder as in FIG. 5 with parts
broken away illustrating the internal passage configuration;
FIG. 7 is a view similar to FIG. 6 illustrating the internal passage
configuration of a sliding cylinder;
FIGS. 8 and 9 show a schematic diagram of a preferred basic hydraulic
operating system used to operate the hydraulic cylinders of the rail car
indexer of the present invention; and
FIG. 10 is a block diagram generally showing the controls used to control
the rail car indexer of the present invention.
DETAILED DESCRIPTION
Referring first to FIG. 1, there is shown generally at 10 portion of a rail
car indexer in accordance with the present invention configured to advance
the cars from left to right with respect to the drawing. A dog of a
progressor of the rail car indexer 10 is shown aligned and engaging a rear
axle 12 of a front bogey frame 14 (based on indexing direction) of a rail
car 16 coupled in series to several other rail cars 18-20 which form part
of a string or trip of cars to be sequentially progressed or indexed. The
car 18 has front and rear bogey frames 21 and 22. For the purpose of this
application and in conformity with general practice in the art, the
distance "A" between the bogey frames 14, 22 of two adjacent cars will
hereinafter be referred to as a "short transfer" distance and the distance
"B" between the front and rear bogeys of a single car will hereinafter be
referred to as a "long transfer" distance.
FIGS. 2 and 3 depict plan views of the general layout of the axle
progressor of the invention in two positions. As seen in the Figures, the
rail car indexer or progressor system 10 has a pair of staggered
progressors including a forward progressor 24 and rearward progressor 26
mounted between the rails of a railroad track in spaced, parallel
relation. Each progressor 24, 26 includes a respective double-acting
stationary or trunnion cylinder 28, 142 in serial connection with a
double-acting tandem or sliding cylinder 30, 144 which itself is serially
connected to a barney or dog operating system 40, 40a.
As best seen in FIGS. 4-7, trunnion cylinder 28 has a rod 54 that is
provided with a connection fitting 33 that is vertically pivotally
connected to the blind end of sliding or tandem cylinder 30 as by clevis
connector 34. The rod 84 of sliding or tandem cylinder 30 also carries a
connection fitting 36 which, in turn, is attached to a frame 38 of barney
40. The barney 40 carries a dog 42 pivotally attached to the frame 34,
wherein the dog 42 is normally held in a fully lowered or stowed position
(cylinder extended) by a heavy compression spring 32s. The dog may be
actuated to the raised and axle engaging position only when the
single-acting, dog-actuating hydraulic cylinder 32 acts to overcome the
spring and retract the cylinder 32. Hydraulic fluid lines as at 44 and 46
are divided into a plurality of segments to supply the cylinders 28, 30
and 32 of the forward progressor 24 with hydraulic fluid in conjunction
with a hydraulic power unit generally 48, as will be explained.
The fluid connections linking the stationary cylinder 28, the sliding or
tandem cylinder 30 and the foremost dog actuating cylinder 32, together
with the internal construction of the trunnion and sliding cylinders 28
and 30 are best pictured in FIGS. 5-7. Each trunnion cylinder 28 has a
hollow internal bore 50 carrying a piston 52 connected to a uniquely
constructed hollow cylinder rod 54. Rod 54 is provided with a longitudinal
central bore 56 which contains a central hydraulic tube 58. The tube 58
which is smaller than the bore 56 extends into a bore in the piston 52
which connects with the blind end of the hollow cylinder bore 50 through a
recessed opening 60 and communicates with the blind end extend port 68. At
the rod end, the tube 58 extends into connection fitting 33 where it
connects with a rod eye extend port at 62. The oversized central bore 56
and central tube 58 of the rod 54 further define an annular chamber 64
surrounding the central tube 58 which is provided with an external
connection in the form of a rod retract port 66. The central tube 58 is
held in place in the central bore 56 of the rod by an open webbing (not
shown). The trunnion cylinder 28 is further provided with a retract port
70 in addition to blind end extend port 68.
As shown in FIG. 7, a similar internal construction is used for tandem or
sliding cylinder 30 in which central internal bore 80 carries piston 82
and cylinder rod 84 itself having a central bore 86 containing a central
tube 88 and defining therewith an annular chamber 94. The tube 88 extends
into piston 82 at the blind end and communicates with the blind end extend
port 98 through opening 90. Tube 88 extends into connection fitting 36 at
the rod end of cylinder 30 where it connects to one access port to the dog
control system at 92. The tandem cylinder 30, as with the trunnion
cylinder 28 is further provided with a rod retract port 96, also connected
to the dog control system along with blind end extend port 98 and a
cylinder retract port 100. As will be described in greater detail below,
the hydraulic system includes several controls that vary the flow and
pressure of the hydraulic fluid to the cylinders 28, 30 and 32. The
consecutive central tubes 58, 88 of cylinders 28 and 30 are serially
connected by an external high pressure hydraulic hose 102 and the annular
chambers 64, 94 of cylinders 28 and 30 are connected via ports 66 and 96
by an external high pressure hydraulic hose 102. The annular chamber 64 of
cylinder 28 is further connected to bore 80 of cylinder 30 at 100. The
annular chambers 64, 94 communicate with respective cylinder bores 50 and
80 through a series of blind end ports 106 and 108 respectively. In this
manner, the rod annular chambers are pressurized with the main cylinder
bores on the power or pull stroke. While FIGS. 4-7 show and the foregoing
description addresses the components of the forward progressor 24, such
equally apply to the rearward progressor 26 as the two are substantially
identical in construction.
FIGS. 2 and 3 further depict plan views of a progressing and hand-off
sequence of the bogey truck or carriage. The progression system of the
invention is designed to sequentially index or spot a trip of 30 or more
cars. FIG. 2 shows the forward progressor 24 fully extended. A pair of
spaced, normally closed, tripper pedal-operated actuating dog valves 110,
112 are provided that are opened by engagement of corresponding tripper
pedals by both the flanges of corresponding wheels on one side of a bogey
carriage 14. The tripper pedals may be of suitable construction and
aligned near the rail such that the flange of the wheel forces the pedal
downward thereby actuating the corresponding dog valve 110, 112. The
forward progressor 24 also includes sequential serially spaced apart
respective extension and retraction proximity switches 114, 116 that, when
actuated, transmit a signal to a programmable logic controller, the signal
being indicative of near full extension and retraction respectively of the
progressor. The forward proximity switch 116 (PX-1L) is shown actuated
closed by the presence of the free end of the forward barney 40. A photo
eye emitter 118 and corresponding receiver 120 are positioned between the
tripper pedal and the stationary cylinder 28.
FIG. 3 shows the rearward progressor 26 fully extended with a corresponding
pair of normally closed tripper pedal-operated dog actuating valves 130,
132 opened by engagement of the flanges of corresponding wheels on the
other side of bogey 14. Similar to the forward progressor 24, the rearward
progressor 26 includes a pair of spaced apart respective extension and
retraction proximity switches 134, 136 that, when actuated, transmit
signals to a programmable logic controller, the signals being indicative
of near full extension and retraction, respectively. The forward proximity
switch 136 is shown actuated closed by the presence of the free end of
rearward barney 40a. The rearward progressor 26 also includes rearward dog
42a pivotally attached to barney 40a, a dog actuating cylinder 138 with
bias spring 140 (see FIG. 8) a trunnion cylinder 142 and a tandem cylinder
144.
The combined maximum stroke of the forward and rearward progressors
(overall stroke) is designed to be sufficient to span the long transfer
distances of rail cars of interest in an installation. This is normally
about 55 feet.
FIGS. 8 and 9 together show the hydraulic schematic for the indexing
system, including valves and switching devices used to control and
coordinate the actuation of the forward and rearward progressors 24 and
26. Connectors A, B, C, and D in FIG. 8 correspond to the like designated
lines of FIG. 9 and interconnect the hydraulic lines of the diagram shown
in FIG. 9 with the stationary cylinders 28 and 142 shown in FIG. 8. As can
be seen from the drawings, lines A and C are used to operate the
corresponding rearward or right progressor 26 and lines B and D to operate
forward or left progressor 24.
The hydraulic system, generally 150, includes an extend or retrieve pump
152 which may be a constant volume gear pump, with output check valve 153,
and a variable volume retract or pull pump 154, both suitably powered by
electric motors as at 156. A suitable fluid reservoir or sump (not shown)
is also provided. The system further includes an extend or retrieve
pressure relief valve 158, and pull pressure relief valve 160. Each of the
lines A, B, C, D is provided with a respective electrically operated
multi-position flow control valve that includes dual solenoid valves.
Thus, line A has extend and retract positioning directional control
solenoid valves 162, 164, respectively; line B, directional extend and
retract control solenoid valves 166, 168; line C has valves 170, 172 and
line D has valves 174, 176. Relief valves are also provided in association
with the operation of the dogs at 178 and 180.
The system further includes a regeneration aspect which will be explained
and which includes regeneration check valve 182, regeneration and back
pressure bypass valve 184. In addition, a unique counter-balance system is
provided that includes a counter-balance valve 190 having a pilot port 192
and check valve 194. The pilot valve is connected via a line 196 with a
shuttle OR valve 198, with associated orifices 200 and 202. A dog bleed
valve is provided at 204. Return lines to sump are shown at 206, 208 and
210.
An aspect of the present invention involves the unique system for
controlling the dogs. The system is designed, as will be recognized from
the FIGS. 8 and 9, so that a dog cannot raise when the corresponding
progressor is extending (retrieving), but only during retraction
(pulling). The maximum setting for the retrieve relief valve 158 is
designed to be below the minimum pressure required to overcome the bias
spring 33, 140 of each respective dog cylinder 32, 138. Thus, even if the
flange operated valves 110, 112 or 130, 132 open due to the presence of a
set of bogey wheels in the extend mode, the fluid pressure is insufficient
to overcome the corresponding bias spring. For example, the design setting
used in the detailed embodiment is normally 750 psi for the retrieve
relief valve 158 and 1000 psi to overcome the dog bias spring.
In the retract or pull mode, the counter balance valve 190 works in
combination with the shuttle OR valve 198 to maintain the pressure
available to the dogs at at least 1000 psi using the 3:1 ratio at the
pilot valve 192 of the counter-balance valve 190 and the counter-balance
valve set at 3000 psi. As can be seen from the diagram, with the
corresponding flow control valve in the retract position as either
progressor 24 or 26 is retracted, oil leaves via the common blind end port
of the trunnion cylinder and proceed through the appropriate solenoid 168,
164 into line 212 from which it can only return to the tank or sump
through counter-balance valve 190 which, in turn, requires that the system
be at 1000 psi to open. This assures that the system pressure will be
adequate to raise the dogs should the respective wheel trippers on the dog
carriage of interest be activated by a rail car wheel.
FIG. 10 shows generally in schematic form the controls for the forward
(left) and rearward (right) progressors 24 and 26. A control panel 250
includes the several pushbuttons and/or other switches that are operated
by the user. The control panel 250 is electrically coupled to a
Programmable Logic Controller (PLC) 252 which includes a central
processing unit (CPU) and all necessary corresponding integrated circuits.
The PLC receives and processes signals from proximity switches 114, 116,
122, photo eye emitter and receiver 118-120 and proximity switches
134-136. These devices and the PLC 252 are electrically powered by a
suitably fused power supply 254. The hydraulic system box 256 includes the
pumps, electrical components including solenoids, the position of which
provide an indication to the PLC the status of each cylinder, and sensors
which indicate the pressure within each corresponding fluid line and the
status of each relief valve or other flow control component suitable
alarms indicated by 258. Alarms 258 are electrically coupled to the PLC
252 and are activated by the PLC 252 depending upon the status of the
progressors 24 and 26.
Having described the constructional features of the present invention, by
way of a detailed example but without any limitation intended, the
preferred mode of operation will next be presented. At the beginning of a
progression cycle for a given trip of cars or when the indexing system of
the invention is to started up at the beginning of a work day, all of the
cylinders are designed to be in the retracted state. When the progressor
is in this position, the dogs are locked down. This retracted, locked down
position is provided to protect the cylinder rods from damage as they will
not be exposed and to make it safe to move cars over the progressor system
in any manner desired. To begin operation, the operator must start the
hydraulic power unit and after an alarm circuit has timed out, with the
hydraulic power unit running, the operator can extend and exercise both
the rearward or left and the forward or right progressors in the normal
sequence without the presence of any railroad cars. This circulates and
warms the oil and insures that the operation of both the cylinders and the
dogs will be smooth when an actual trip of cars is being advanced. After
this has been accomplished, the system is ready to address an actual trip
or string of cars.
The operation of one progressor of the system will first be described with
reference to FIGS. 8 and 9. As can be seen from the schematic diagram, the
operation of the other is identical. To extend the forward progressor,
relief valve 158 and solenoids 166 and 176 are energized. In this manner,
oil is pumped out of the gear pump 152 through the pilot check valve 153
through the directional control valve and into the blind end of cylinder
28 along line "B" and the cylinder begins to extend. While cylinder 28 is
extending, oil also travels into the blind end of cylinder 30 via tube 58
through the inside of cylinder 28 and connection line 102 (FIG. 5). This
oil, in turn, travels to relief valve 180 but both valves 110 and 112 are
closed and the pressure is, in any event, insufficient to operate the dog
cylinder 32 so that the oil will stop at this point. The rod ends of
cylinders 28 and 30 are also connected to each other via line 104 (FIG. 5)
and internal tubing in the cylinders (see FIGS. 6 and 7). In this manner,
hydraulic fluid displaced from the rod ends of the cylinders by the
movement of the pistons along the cylinders is collectively expelled from
the rod end of cylinder 28 via conduit "D". This hydraulic fluid returns
via solenoid valve 176 and line 214 through check valve 182 where it
combines with oil being pumped from pump 152 to accomplish regeneration.
In no event does the pressure in the system during extension exceed the
setting of relief valve 158 which is below the minimum required to raise
the dogs.
The retraction of the forward or pull cylinder with the dogs active
requires energizing dog or pull relief valve 160 and flow control
solenoids 168 and 174. Hydraulic fluid from the piston pump 154 is
conducted through the valve at 174 along line "D" and into the rod end of
cylinder 28 at 70. Part of the oil splits off and travels through the
orifice 200 and the shuttle valve 198 to 3:1 pilot port 192 of
counter-balance valve 190. The oil traveling into the rod end of cylinder
28 also via interconnections mentioned above enters the rod end of
cylinder 30 and the cylinders begin to retract. This oil also travels to
rail tripper-operated valve 110 awaiting the operation of the wheel
tripper going under a rail car wheel. Of course, the blind ends of
cylinders 30 and 28 are connected by external connection 102 (FIG. 5) and
by the internal passages previously explained such that the oil expelled
in retracting the cylinders exits via conduit "B" through valve 168 and
line 212 to counter-balance valve 190 where the pressure will build until
it reaches 1000 psi which is required with the 3:1 pilot port to operate
the counter-balance valve 190, which when open, allows the returning oil
to be passed to the tank or sump via line 210. Since the pressure is
maintained in a minimum of 1000 psi, if both wheels trippers are activated
at the same time, valves 110 and 112 will open and oil will be allowed to
the rod end port of the dog cylinder 32 thereby raising the dog.
Initially, a locomotive is used to position or spot a string or trip of
cars within range of a stowed (locked down) forward progressor as at 24.
Once the cars are in range, progression of the rail cars may be
accomplished automatically with the forward and rearward progressors 24
and 26.
To begin movement of the string of cars, the operator closes a switch on
the control panel 90 which is designated as a "move cars" switch. After a
preset time delay with appropriate audible warning or alarm, the forward
progressor 24 begins retracting. An interlock system is provided that
inhibits initial movement of the forward progressor 24 if a wheel of the
car is located so as to actuate closed one or both of the tripper-operated
valves 110, 112. When the tripper-operated valves 110, 112 are depressed
by a wheel, the beam from the photo eye emitter 118 is also interrupted or
broken, indicating or verifying that the tripper-operated valves 110, 112
are held opened. This is part of an interlock system that avoids raising
of the forward dog 38 when the first car in the string of cars has not
been positioned in the proper range of the forward trunnion cylinder 28
and prevents a dog from raising between the axles of a common bogey frame
which could cause damage to the car.
Assuming proper car positioning, once the forward progressor 24 begins
retracting slowly, the forward barney 40 is pulled under the forward or
first encountered set of wheels of the first car in the string of cars.
When the wheels are aligned above the tripper pedals and the valves 110
and 112 are both actuated open, the forward dog 42 is caused to raise and
it engages the second encountered or rear axle of the forward bogey
carriage. The speed of retraction is preferably programmed to be increased
automatically once the axle is engaged, but of course, it may
alternatively be increased or decreased manually. This is accomplished by
varying the variable volume output of pull pump 154, which may be 0-45 gpm
or the like. Maximum speed is normally about 50 fpm at 45 gpm. The
retraction of forward progressor 24 continues until the rearmost proximity
switch 114 is actuated closed. Thereafter, the retraction of forward
progressor 24 slows until cylinders 28 and 30 are fully retracted.
When the cylinders 28 and 30 are fully retracted, the rearward progressor
begins retracting. When the wheels of the forward bogey actuate the
tripper pedals and close the rearward tripper valves 130 and 132, the
rearward dog 42a raises and engages the rear axle of the forward bogey.
The rearward progressor 26 then retracts pulling the train towards the
rearward stationary cylinder 142. As the rearward progressor retracts, the
car is "handed-off" and the forward dog 38 lowers and the forward
progressor 24 begins to extend. The speed of retraction of the rearward
progressor may then be increased either manually or automatically. During
the retraction of the rearward progressor 26, the photo eye emitter 118 is
active. When the beam is broken twice by the rail car wheels actuating the
corresponding tripper pedal, the speed of rearward progressor 26 is
decreased.
The forward progressor 24 then begins retracting slowly until both tripper
pedals are actuated by the bogey wheels. The forward dog 38 then rises and
the pulling of the rail car is transferred to the forward progressor. As
the forward progressor 24 continues to retract, the rearward progressor 26
"looks" for the next bogey to grab and pull. This pull and handoff
arrangement continues as needed until all of the rail cars have been
pulled past the progressors 24 and 26. The operator may stop the
progressor at any time so that a car may be processed, and the progressors
24 and 26 will continue the progression once they are re-activated.
Once the last car of a trip or string has been pulled through, an automatic
dog lock-down system is provided so that the operator can lock down the
dogs after a sufficient time delay and appropriate alarm. Dog lock down is
accomplished by first extending the forward progressor to make room for
the dog to drop if it is presently against an axel. Once this is
accomplished, the forward progressor will retract its full stroke with its
dog down. In this sequence, the counterbalance valve is by-passed and oil
flows through by-pass valve 184 directly to the sump so that pressure
cannot reach the 1000 psi necessary to raise a dog. When the carriage
reaches the full stroke, it will continue to retract for a preset amount
to insure that it is fully retracted. Once this is complete, the rearward
progressor will go through the same procedure. When this is finished, the
dog lock-down cycle is complete. Movement will stop and a panel indication
will show that the dogs are safely locked down so that cars may be again
moved over the system as desired.
This invention has been described herein in considerable detail in order to
comply with the patent statutes and to provide those skilled in the art
with information needed to apply the novel principles and to construct and
use such specialized components as are required. However, it is to be
understood that the invention could be carried out by specifically
different equipment and devices, and that various modifications, both as
to the equipment details and operating procedures, can be accomplished
without departing from the scope of the invention itself.
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